Air bag device

ABSTRACT

There are provided an inflator  31 ; a cylindrical holder  32  where the inflator  31  is accommodated inside; and a bag-shaped airbag  35  accommodating the holder at it&#39;s opening portion  34  and folded in an ordinary situation to be expandable by a gas G discharged from the inflator  31 , wherein a protecting cloth  50  distinct from the airbag  35  is arranged on an inner face of the opening portion  34  of the airbag  35.

TECHNICAL FIELD

The present invention relates to an-airbag apparatus whichinstantaneously expands to protect a passenger of his/her own automobileat a time of a collision of an automobile, particularly so-called alateral collision where another automobile collides against a sideportion of his/her own automobile.

BACKGROUND ART

As an airbag apparatus for protecting a passenger, there is, forexample, one disclosed in U.S. Pat. No. 5,586,782 or one disclosed inJapanese Patent Application Laid-Open No. 8-207689.

The former, namely an airbag apparatus for lateral collision (DUALPRESSURE SIDE IMPACT AIRBAG) disclosed in U.S. Pat. No. 5,586,782, isconfigured such that, at a time of a lateral collision of an automobile,an electrical signal is transmitted to an inflator via a harness forignition when the collision is detected, gas generated from the inflatorignited is introduced from a gas discharging hole into an airbag foldedto be accommodated within a case body in a backrest in an ordinarysituation of the automobile to expand the same, the expanded airbagpresses and opens a lid of the case body, and the airbag is spreadbetween a passenger and a passenger compartment side wall, so that animpact generated when the passenger secondarily collides against thepassenger compartment side wall is absorbed by the airbag.

The airbag is structured such that a bag body formed in a generallyL-shaped configuration with a head protecting portion and a chestprotecting portion is divided into a gas passage to the head protectingportion and a gas passage to the chest protecting portion by a dividingplate or a sewn portion, and the gas discharged from the inflator isfilled into the respective protecting portions in a short time.

Also, the latter, namely an airbag for lateral collision disclosed inJapanese Patent Application Laid-Open No. 08-207689, is structured suchthat an airbag is folded and accommodated within a backrest in anordinary situation of an automobile, like the former, and at a time of alateral collision of an automobile the airbag is abruptly expanded bydischarged gas rapidly from an inflator into the airbag via a supportingpipe so that an impact generated when a passenger secondarily collidesagainst a passenger compartment side wall is absorbed by the airbag.

However, in a structure of such a conventional airbag apparatus, as theinflator (the former) or the supporting pipe (the latter) is housed inthe airbag of the airbag apparatus from an opening portion thereof,there is a risk that an inner face of the airbag may be injured byfriction between the airbag and an edge portion of the inflator or aholder for holding the inflator inside the airbag.

Also, the gas discharged from the inflator tends to concentrate on thevicinity of an inflator-mounting portion positioned at the openingportion of the airbag, which is required to be improved.

The present invention has been achieved in view of the problems in sucha conventional art, and an object thereof is to provide an airbagapparatus which prevents the friction between the airbag and the edgeportion of the inflator or the holder for holding the inflator insidethe airbag and the injury of the airbag due to a high temperature gasdischarged from the inflator.

DISCLOSURE OF INVENTION

In order to achieve the above object, the invention of a first aspectcomprises: an inflator; and an airbag accommodating the inflator at itsopening portion and folded in an ordinary situation to be expandable bya gas discharged from the inflator, wherein a protecting cloth distinctfrom the airbag is arranged on an inner face of the opening portion ofthe airbag.

According to the invention of the first aspect, the airbag can beprevented by means of the protecting cloth from being injured byfriction between the airbag and an edge portion of the inflator and ahigh temperature gas discharged from the inflator.

The invention of a second aspect comprises: an inflator; a cylindricalholder inside which the inflator is accommodated; and an airbagaccommodating the inflator at its opening portion and folded in anordinary situation to be expandable by the gas discharged from theinflator, wherein a protecting cloth distinct from the airbag isarranged on an inner face of the opening portion of the airbag.

According to the invention of the second aspect, the airbag can beprevented by means of the protecting cloth from being injured byfriction between the airbag and an edge portion of the holder forholding the inflator inside and a high temperature gas discharged fromthe inflator.

As a preferred aspect, a portion of the protecting cloth positioned at aside which is supported by an inside part of an automobile is thickerthan a portion of the protecting cloth positioned at a side which is notsupported by the inside part.

According to this aspect, even when friction occurs between the airbagand an edge portion of the inflator or the holder, there is a marginwhere the friction can freely be avoided in the portion of theprotecting cloth positioned at the side which is not supported by theinside part, whereby the airbag itself can securely be protected bymaking thick the portion of the airbag positioned at the side wherethere is not the margin. Also, the portion of the protecting clothpositioned at the side which is supported by the inside part which isapt to be influenced by the high temperature gas discharged from theinflator is made thick, so that the airbag itself can securely beprotected.

Also, as a preferred aspect, a heat resistant temperature at a portionof the protecting cloth positioned at a side which is supported by aninside part of an automobile is higher than that at a portion of theprotecting cloth positioned at a side which is not supported by theinside part.

According to this aspect, even when friction occurs between the airbagand the edge portion of the inflator or the holder, as the portion ofthe protecting cloth positioned at the side which is not supported bythe inside part is apt to be air-cooled, the heat resistant temperatureof the portion of the protecting cloth positioned at the side which issupported by the inside part is made high, so that the airbag itself cansecurely be protected.

As a further preferred aspect, the opening portion of the airbag isformed so as to be overlapped at its supporting portion for supportingthe inflator or the holder accommodating the inflator inside thereof,and a reinforcing cloth which is to resist against the heat of the gasdischarged from the inflator is held on the overlapped portion.

According to this aspect, as the airbag is prevented from being injuredby direct discharge of the inflator without increasing the number ofcomponent parts, the number of airbag forming steps such as sewing canremarkably be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a whole perspective view of a seat mounted with an airbagapparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view taken along line II—II in FIG. 1;

FIG. 3 is a sectional view showing a state where an airbag has beenexpanded from a state shown in FIG. 2;

FIG. 4 is an exploded side view of only the airbag of FIG. 2 at anexpanded time, a holder, and the like;

FIG. 5 is a sectional view taken along line V—V in FIG. 4; and

FIG. 6 is a sectional view taken along line VI—VI after a bolt member 38is inserted into through holes 56 a and 57 a of a first reinforcingcloth 56 and a second reinforcing cloth 57.

BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 to 6 show an embodiment. As shown in. FIGS. 1 and 2, a seat 1comprises a backrest 2 and a seat cushion 3, and the backrest 2 isarranged at a position opposing to a passenger compartment inner sidewall 4 such as a door trim, a center pillar inner panel 5 or the like. Areference character 6 denotes a head rest, a reference character 7denotes a lap belt, and a reference character 8 denotes a shoulder belt.

As shown in FIGS. 2 and 3, the backrest 2 comprises a backrest frame 10;a cushion pad 11 arranged at a front side FR of the backrest frame 10; aside cushion 12 arranged on a side SD of the backrest frame 10; a firstshock absorbing member 13 of a slab urethane type arranged at the frontside FR of a central portion CT of the cushion pad 11; a first outerskin 14 covering the first shock absorbing member 13; a second shockabsorbing member 15 of a slab urethane type arranged at the front sideFR on the side SD of the cushion pad 11; a second outer skin 16 coveringthe second shock absorbing member 15; a third shock absorbing member 17of a slab urethane type arranged on the side SD of the side cushion 12;a third outer skin 18 covering the third shock absorbing member 17; anairbag apparatus 19 arranged between a side portion of the cushion pad11 and an inner face of the side cushion 12 by means described later; asewn portion 20 holding the first shock absorbing member 13, the firstouter skin 14, the second shock absorbing member 15, and the secondouter skin 16; an opening and rupturing portion 21 configured by sewingthe second shock absorbing member 15, the second outer skin 16, thethird shock absorbing member 17, and the third outer skin 18 so as to beruptured by a predetermined pressure; a cloth-like protecting member 23for protecting the side cushion 12, one side of which is sewn to theopening and rupturing portion 21, the other side thereof being held by awire of the backrest frame 10; and a sewn portion 24 holding the sidecushion 12, the third shock absorbing member 17 and the third outer skin18.

As shown in FIG. 4, the airbag apparatus 19 comprises a verticallyelongated cylindrical holder 32 where an inflator 31 is accommodated,the inflator being capable of being ignited by transmission of acollision electric signal from an unillustrated sensor through anignition harness 30; an airbag 35 arranged such that its opening portion34 faces a discharging hole 33 of the holder 32 and folded in anordinary situation of an automobile to be expandable by a gas Gdischarged from the inflator 31; and a case body 37 (refer to FIG. 2)made of synthetic resin, the case body 37 covering the holder 32 and theairbag 35 and having an opening portion 36 rupturable by expansion ofthe airbag 35.

As shown in FIGS. 4 and 6, bolt members 38 are provided in a projectingmanner on the holder 32. The bolt members 38 are exposed outside viaunillustrated through holes of the case body 37 and they are insertedinto unillustrated through holes to be screwed to nuts 40. At this time,the discharging hole 33 of the holder 32 faces on the front side FR andit is arranged at a lower side DW.

As shown in FIG. 1, the airbag 35 is formed in a bag shape so as to beexpandable in a generally L configuration with a head protecting portion41 and a chest protecting portion 42 by the gas G discharged from theinflator 31, and it is folded in an ordinary situation of an automobile.

A protecting cloth 50 distinct from the airbag 35 is arranged on aninner face of the opening portion 34 of the airbag 35.

The protecting cloth 50 comprises a first protecting cloth 51 attachedto an inner face of the airbag 35 positioned at a side (a side opposedto or facing a side which is supported by an inside part) which is notsupported by the backrest frame 10 or the like and a second protectingcloth 52 and a third protecting cloth 53 attached in layers to an innerface of the airbag 35 positioned at a side which is supported by theinside part. The plate thickness of the second and third protectingcloth 52 and 53 is thicker than that of the first protecting cloth 51.The second and third protecting cloth 52 and 53 are not put in layersbut they may be configured in one piece.

In the protecting cloth 50, the heat resistant temperatures of thesecond and third protecting cloth 52 and 53 are preferably higher thanthat of the first protecting cloth 51.

The first protecting cloth 51 and the third protecting cloth 53 arerespectively formed in the almost same size as those of the left and theright cloth 35 a and 35 b configuring the airbag 35. The secondprotecting cloth 52 is arranged at a position nearest to the inflator31, and it is formed in a size approximating to the discharging hole 33,namely half a vertical size of each of the first protecting cloth 51 andthe third protecting cloth 53.

The opening portion 34 of the airbag 35 is folded at a supportingportion 55 for supporting the inflator 31 or the holder 32 accommodatingthe inflator 31 therein so as to be overlapped, and a first reinforcingcloth 56 and a second reinforcing cloth 57 capable of resisting againstthe heat of the gas discharged from the inflator 31 are held on thesupporting portion 55 thus overlapped. A reference characters 56 a and57 a are through holes formed on the first reinforcing cloth 56 and thesecond reinforcing cloth 57 so as to be insertable with the bolt members38, respectively. As shown with a cross-sectional view of the airbagapparatus in FIG. 6, the first reinforcing cloth 56 is positioned nearerto the holder 32 than the second reinforcing cloth 57. Accordingly, evenwhen the airbag 35 is injured by a corner of the discharging hole 33side of the inflator 31, the airbag 35 is prevented from being worn outby extending the first reinforcing cloth 56 sufficiently towards thedischarging hole 33 side of the inflator 31, and the airbag 35 itself issecurely protected so that the airbag can securely be spread.

As the embodiment of the invention is structured in the above manner,when the inflator 31 is ignited by any signal so that the gas G isdischarged from the discharging hole 33 of the holder 32 as shown with awhite arrow in FIG. 3, the airbag 35 which has been folded in anordinary situation, particularly the chest protecting portion 42, israpidly expanded towards the front side FR of the automobile by the gasG discharged from the inflator 31, and the opening portion 36 of thecase body 37 covering the airbag 35 is put in a ruptured state, so thatthe case body 37 is opened in a linear shape and the airbag 35 isfurther expanded.

That is, as the chest protecting portion 42 of the airbag 35 which hasbeen folded in the ordinary situation is first expanded and then the gascan be introduced into the head protecting portion 41 side, the chestprotecting portion 42 enters securely in between the chest of apassenger, and the door trim 4 and the center pillar inner panel 5, sothat a secondary collision energy of the passenger against the door trim4 and the center pillar inner panel 5 can sufficiently be absorbed.

Injury of the airbag 35 due to friction between the airbag 35 and theedge portion of the holder 32 holding the inflator inside and the hightemperature gas G discharged from the inflator 31 can be prevented bythe protecting cloth 50.

Even when friction occurs between the airbag and the edge portion of theinflator 31 or the holder 32, as the cloth 35 b of the airbag 35positioned at the side which is not supported by the inside part has amargin where it can avoid the friction freely, the cloth 35 a of theairbag 35 positioned at the side in which there is not the margin ismade thicker by the third protecting cloth 53, thereby allowing a secureprotection of the airbag 35 itself.

Also, the cloth 35 a of the airbag 35 positioned at the side which issupported by the inside part which is apt to be influenced by the hightemperature gas G discharged from the inflator 31 is made thicker,thereby allowing a secure protection of the airbag 35 itself.

Even when friction occurs between the airbag and the edge portion of theinflator 31 or the holder 32, as the cloth 35 b of the airbag 35positioned at the side which is not supported by the inside part is aptto be air-cooled. Accordingly, the heat resistant temperature of thecloth 35 a of the airbag 35 positioned at the side which is supported bythe inside part is made higher, thereby allowing a secure protection ofthe airbag 35 itself.

As the injury of the airbag 35 due to direct discharge of the gas G fromthe inflator 31 can be prevented without increasing the number ofcomponent parts, the number of steps for forming the airbag 35 such assewing can remarkably be reduced.

The above explanation is directed to an explanation of the case wherethe holder 32 is used, but the invention may be structured such that theinflator 31 is arranged directly at the opening portion 34 of the airbag35. Even in such a case, the injury of the airbag 35 due to the frictionbetween the airbag and the edge portion of the inflator 31 and the hightemperature gas G discharged from the inflator 31 can be prevented bythe protecting cloth 50.

INDUSTRIAL APPLICABILITY

As mentioned above, the airbag apparatus according to the presentinvention is useful as an apparatus for protecting a passenger at a timeof collision of an automobile.

What is claimed is:
 1. An airbag apparatus for lateral collisioncomprising: a normally folded airbag having a first base cloth and asecond base cloth sewn to each other to define an opening portion; aninflator device for discharging a gas to expand the airbag, the inflatordevice being accommodated inside the opening portion, the inflatordevice having an edge and being supported via the first base cloth; anda protecting cloth separated from the airbag, the protecting clothhaving a first protecting cloth and a second protecting cloth, the firstprotecting cloth being arranged on the first base cloth inside theopening portion, the second protecting cloth being arranged on thesecond base cloth inside the opening portion; wherein a section of theairbag including both the first base cloth and second base clothportions defining the opening portion is folded back over the first basecloth and positioned corresponding to the inflator device, and whereinthe airbag apparatus further comprises a reinforcing cloth, thereinforcing cloth being held on the end of the opening portion.
 2. Anairbag apparatus according to claim 1, wherein said reinforcing clothcomprises a first reinforcing cloth disposed on an outer surface of thefirst base cloth.
 3. An airbag apparatus according to claim 2, whereinsaid reinforcing cloth further comprising a second reinforcing clothattached to an outer surface of the second base cloth.
 4. An airbagapparatus according to claim 3, wherein said first reinforcing cloth andsaid second reinforcing cloth are disposed to substantially align withone another when the opening portion of the airbag is folded back overthe first base cloth.